diff --git a/t/Dockerfile b/t/Dockerfile
index 7b6b16c..0295673 100644
--- a/t/Dockerfile
+++ b/t/Dockerfile
@@ -5,7 +5,7 @@ FROM docker.mgm.sipwise.com/sipwise-bullseye:latest
 # is updated with the current date. It will force refresh of all
 # of the base images and things like `apt-get update` won't be using
 # old cached versions when the Dockerfile is built.
-ENV REFRESHED_AT 2021-05-03
+ENV REFRESHED_AT 2023-03-24
 
 RUN apt-get update && \
     apt-get install --assume-yes \
@@ -17,6 +17,8 @@ RUN apt-get update && \
 
 RUN echo './t/testrunner' >>/root/.bash_history
 
+RUN git config --global --add safe.directory /code
+
 WORKDIR /code/
 
 ################################################################################
diff --git a/t/testrunner b/t/testrunner
index b39367a..40a93ab 100755
--- a/t/testrunner
+++ b/t/testrunner
@@ -36,6 +36,16 @@ if [ -z "${branch:-}" ] ; then
   branch="none"
 fi
 
+# only run inside docker environments as root user
+if [ -f /.dockerenv ] && [[ "$(id -u)" == "0" ]] ; then
+  # the environment passed to docker might claim to have
+  # /var/lib/jenkins for $HOME, but we might be running
+  # under user root, so ensure the ~/.gitconfig can be found
+  # at the appropriate place
+  echo "Fixing HOME for user root (changing from '${HOME}' to '/root')"
+  export HOME=/root/
+fi
+
 if [[ "${release}" =~ ^release-mr ]] ; then
   echo "release detected"
   short_release=${release%%-update}